The prenatal diagnosis of ventral abdominal wall defects

Antenatal diagnosis and perinatal care of anterior abdominal wall defects

Improvements in anaesthetic care and postoperative management over the last two decades have significantly improved survival of neonates with ventral abdominal wall defects, from a dismal 47% in 1971, to 96% for both gastroschisis and isolated omphalocele in two recent series. This increased survival has generally been attributed to result from improvements in the pre and postoperative management of these fragile neonates. Specifically, the routine use of total parenteral nutrition, and staged repairs for cases with severe “viscero-abdominal disproportion” have been implicated in a decreased incidence of sepsis, morbidity and mortality. In addition, an appreciation of the wide spectrum of anomalies uniquely associated with gastroschisis and omphalocele have helped improve survival, as each has unique pathophysiologic features that have prognostic implications for the fetus before, during and after delivery.

Prenatal detection of pulmonary hypoplasia in giant omphalocele

Respiratory insufficiency has sometimes been reported in giant omphalocele. To determine whether ultrasonic fetal lung measurements including lung/thorax transverse area ratio (L/T) and chest/trunk length ratio (C/T) may be useful in predicting associated pulmonary hypoplasia, 28 fetuses with abdominal wall defects between 1991 and 2003 were reviewed. Nine patients with gastroschisis and 19 with omphalocele were classified into three groups. A group with neonatal death and postmortem lung/body weight ratio below 0.012, which was defined as pulmonary hypoplasia (PH group), included two ruptured giant omphaloceles and two giant omphaloceles with intact covering membrane in utero. A group with artificial ventilation more than 3 months, which was defined as prolonged ventilation (PV group), included one ruptured giant omphalocele and three giant omphaloceles with intact covering membrane. Others were defined as ordinary group. In 12 fetuses with giant omphalocele, the evisceration rate of the liver (LER) was measured in the fetal transverse abdominal dimension including the base of the liver. The L/T in PH group was significantly decreased to other groups. The C/T in PH group was significantly increased to ordinary group. There was no significant difference in the LER among three groups. A measurement of L/T may be useful in predicting associated pulmonary hypoplasia in giant omphalocele. However, antenatal detection of patients required prolonged ventilation may be difficult and require further study.

Cesarean delivery for fetal malformations

We reviewed existing data on fetal abnormalities to provide guidelines to determine which conditions have an improved neonatal outcome by cesarean delivery. We used Medline database to search for English language papers on a variety of fetal conditions that could influence the mode of delivery. We reviewed these sources with particular attention to how the mode of delivery influenced neonatal outcome. Conflicting data exist regarding optimal mode of delivery for many fetal conditions. Cesarean delivery may improve neonatal outcome for fetuses with isolated meningomyelocele, hydrocephalus with concomitant macrocephaly, anterior wall defects with extracorporeal liver, sacrococcygeal teratomas, hydrops, and alloimmune thrombocytopenia with low platelet count at term. Hydrocephalus without macrocephaly, anterior wall defects without an extracorporeal liver, ovarian cysts, skeletal dysplasias, fetuses whose mothers have immune thrombocytopenic puer-pura and fetuses with alloimmune thrombocytopenia with acceptable platelet counts may safely be delivered vaginally.

Prenatal diagnosis of abdominal wall defects and their prognosis

To determine whether associated anatomic features may be useful in predicting fetal prognosis, 43 fetuses who had ultrasonographic evaluation for abdominal wall defects during a 13-year period were reviewed. Thirty-one fetuses had omphalocele and were classified into three groups according to fetal ultrasonography results: ruptured omphalocele with exposed liver, giant omphalocele with exposed liver, and small omphalocele without liver herniation. Twelve fetuses had gastroschisis. Ten of the 12 fetuses with gastroschisis survived; one died in utero. Nine of the 12 with a small omphalocele survived. Ten of 12 fetuses with giant omphalocele survived, but six of the seven with ruptured omphalocele died of pulmonary hypoplasia and respiratory insufficiency. Ruptured omphalocele recognized in utero was accompanied by intrauterine growth retardation and liver herniation and frequently was associated with deformity of the spine, diaphragmatic defects, vesicointestinal fissure, and meningocele. These results indicated that, together with the deformity of the spine, rupture and absence of the covering membrane with an exposed liver (noted through fetal ultrasonography) may suggest a poor prognosis because of pulmonary hypoplasia.

Specificity of antenatal ultrasound in the Yorkshire Region: a prospective study of 2261 ultrasound detected anomalies

OBJECTIVE

To evaluate the specificity of the ultrasound diagnosis of fetal anomalies. Pregnancies which proceeded to termination and ultrasound-diagnosed fetal anomalies which were not offered termination were considered.

DESIGN

Prospective, region-wide study over three and a half years.

SETTING

Cases were identified through 25 ultrasound departments representing the 15 districts in the Yorkshire Region.

SUBJECTS

Pregnant women with an ultrasound-diagnosed fetal anomaly.

MAIN OUTCOME MEASURES

Information obtained from the ultrasound report was compared with the outcomes determined by cytogenetics, postmortem or paediatric examination.

RESULTS

Of 2261 pregnancies with an ultrasound-diagnosed fetal anomaly 369, (16%) were terminated and 357 (97%) were followed by postmortem examination. Ultrasound findings exactly matched those of the postmortem or were accompanied by additional anomalies in 325 cases (91%). In 32 cases ultrasound findings were not confirmed by postmortem, but in 30 of these the decision to offer termination remained justified because the correct diagnosis was judged equally or more serious. Two (0.5%) were terminated for an anomaly which subsequently proved less severe than predicted on ultrasound. Ultrasound significantly over- or under-diagnosed a major fetal anomaly in 27 of the 1139 (2.4%) cases in which an anomaly was detected, but the pregnancy was not terminated.

CONCLUSION

Termination of pregnancy was based on the correct prognosis in over 99.5% of cases. This does not obviate the need for pathological examination of the fetus which changed or refined the diagnosis in 35% of cases.

Omphalocele and gastroschisis: a collaborative study of five Italian congenital malformation registries

During 1984-1989, 116 cases of omphalocele and 42 cases of gastroschisis were detected among 736,760 consecutive births in the area covered by five Italian congenital malformation registries. The prevalence rate was 1.6 per 10,000 for omphalocele and 0.6 per 10,000 for gastroschisis. Three additional cases were detected among spontaneous abortions, giving a total of 117 cases of omphalocele and 44 of gastroschisis. No variations in prevalence rates were observed among registries. A cluster of omphalocele was found in 1989 in Firenze. All cases were sporadic except for one infant with two sibs with Beckwith-Wiedemann syndrome. A predominance of male infants was observed for both defects. This study confirms the very young maternal age for isolated gastroschisis as compared to that for omphalocele and controls. Birth weight and the percentage of small-for-date is different among isolated gastroschisis, omphalocele and controls. Associated anomalies occurred in 45 cases of omphalocele and 11 cases of gastroschisis. Our data confirm the association of omphalocele with trisomies 13 and 18. Twelve cases of omphalocele and gastroschisis with associated limb defects were classified as limb body wall complex. The possible differences in etiopathology between omphalocele and gastroschisis, both isolated and associated, are discussed.

Antenatal fetal diagnosis and maternal transport gastroschisis. A maternal-infant case report

Gastroschisis is a rare congenital birth defect of the abdominal wall that invariably is fatal if not managed appropriately. Early in utero diagnosis is now possible using maternal serum alpha-fetoprotein and ultrasound. As with other serious congenital disorders, antenatal diagnosis allows therapeutic options and time for preparation. Even if the diagnosis is made late, however, efforts to achieve prenatal maternal transport are still reasonable. The neonatal outcome of an unplanned delivery of an anomalous child requiring immediate attention is likely to be better if the delivery occurs in a tertiary center. These facilities generally have specialized services and teams available for critical care around the clock. The authors describe the maternal transport and delivery of a neonate with a serious disorder that required specialized attention at an hour when most hospitals are staffed with a skeleton crew. The necessary resources were available immediately, and the neonatal outcome was favorable. Although this report describes gastroschisis specifically, the concept of tertiary site delivery for potentially seriously ill neonates applies to any condition. With a late diagnosis, possible other anomalies, and a logistically unfavorable hour, the advantages of maternal transport are evident. This report also briefly reviews the area of antenatal ultrasound diagnosis and the newer mechanisms used to develop a perinatal care plan.

Cesarean section does not improve outcome in gastroschisis

Elective cesarean section (CS) following prenatal diagnosis of gastroschisis has been advocated to decrease morbidity and mortality. To examine this hypothesis, we reviewed the records of 28 consecutive patients with gastroschisis treated between 1975 and 1987. Fourteen infants were delivered vaginally (V) and fourteen by CS, of which seven were elective, five were for fetal distress, and two were for breech presentation. Prenatal diagnosis was made in nine infants in the CS group and none in the vaginal group. The two groups were comparable in gestational age (V = 37.6 weeks, CS = 35.8 weeks, P = .05), birth weight (V = 2,508 g, CS = 2,444 g, P = NS), and five-minute Apgar score (V = 7.8, CS = 6.8, P = NS). Outcome was similar as measured by hospital mortality (V = 0/14, CS = 1/14, P = NS), complications (V = 4/14, CS = 5/14, P = NS), days to enteral feeding (V = 14, CS = 19, P = NS), and days in the hospital (V = 27, CS = 34, P = NS). The only complication related to mode of delivery was preventable; an infant delivered vaginally had avulsion of a short segment of mesentery requiring bowel resection. Infants born by CS were slightly more likely to have primary closure (5/14) than babies delivered vaginally (3/14, P = NS), but this may reflect independent trends in the last 5 years. Elective CS following prenatal diagnosis in seven patients did not improve outcome; primary closure was achieved in only one infant, and three had a complication. Since these data show no significant difference in morbidity and mortality between vaginal and CS delivery, we suggest that CS should not be recommended simply because a prenatal diagnosis of gastroschisis is made.